Composite materials are known and are used, for example, for components of heat carriers or heat exchangers in aircrafts or motor vehicles. Thus, carrier materials made of a corrosion-sensitive aluminum alloy may be coated with alloys, which have at least one corrosion potential-reducing element, for example zinc, tin or indium. These are frequently subjected to a heat treatment at temperatures of above 450° C., for example 575° C. to 610° C., when soldering the heat exchanger. The use of zinc as a corrosion potential-reducing element is, however, affected by the problem that zinc may diffuse rapidly and scarcely controllably from the corrosion protection layer into the carrier material. This leads to the fact that the carrier material also becomes baser and more susceptible to corrosion. Furthermore, zinc-containing corrosion protection layers also experience a rapid material removal owing to corrosive media, as the depth of the attack and material removal by corrosive media cannot be controlled. The corrosion protection brought about by zinc is therefore of a comparatively short duration. The use of tin and/or indium as a corrosion potential-reducing element is problematical, on the other hand, in that their presence severely impairs the recyclability of the alloys, as fractions of tin or indium in aluminum alloys are only suitable for a few applications. The tin and/or indium fractions therefore would firstly have to be laboriously separated out in order to be able to recover aluminum of high purity which is suitable for diverse applications.
Furthermore, it is known to coat a carrier material made of an aluminum-manganese alloy with a coating made of an aluminum-silicon alloy. In this composite material, for example at temperatures of 575° C. to 610° C., silicon diffuses from the applied layer out of an aluminum-silicon alloy into the carrier material and causes precipitations of manganese compounds in the manganese-supersaturated mixed crystals of the carrier material. The corrosion potential of the precipitated manganese compounds is lower than the corrosion potential of the remaining carrier material, so the precipitated manganese compounds can act as a corrosion protection. However, the depth to which the silicon diffuses into the carrier material, and therefore the thickness of the layer having the precipitated manganese compounds, sensitively depend on the process conduct during the production of the composite material and on the heat treatment. This requires a high degree of precision and also complex process monitoring techniques during production.